AMD RYZEN Particles and Physics Simulations optimization needed
Physics calculations are extremely hard to thread and there is, as far as I know, no magic setting to change this. Think of it this way. Rendering you can do frame one and frame ten at the same time. Frame ten doesn't depend on the result of frame one. In physics simulations core two can't start work till core one finishes since it needs its data. Their is some performance improvements as some of the calculations can be threaded, but overall processor speed is the far more important factor.